Integrated circuit performance improvement across a range of operating conditions and physical constraints

ABSTRACT

Methods and apparatus to improve integrated circuit (IC) performance across a range of operating conditions and/or physical constraints are described. In one embodiment, an operating parameter of one or more of processor cores may be adjusted in response to a change in the activity level of processor cores (e.g., the number of active processor cores) and/or a comparison of one or more operating conditions and one or more corresponding threshold values. Other embodiments are also described.

BACKGROUND

The present disclosure generally relates to the field of electronics.More particularly, an embodiment of the invention relates to improvingintegrated circuit (IC) performance across a range of operatingconditions and/or physical constraints.

Generally, an IC may be designed to operate within a specificenvironment. Such constraints may include physical parameters such as anallowable operating temperature range and an allowable operating voltagerange. These parameters and specifications may be determined based onthe worst case operating conditions. However, such configurations mayprovide a substantial difference between a typical operating point andthe worst case operating point.

Moreover, when a product is tested in a high volume manufacturingenvironment, the operating parameters may be adjusted to ensure that anindividual processor meets the relevant specifications, and that it mayoperate correctly and reliably within the described environment. Inorder to ensure that all relevant specifications are met, the operatingfrequency and voltage may be adjusted with fuses on a part-by-partbasis. As a result of this set of specifications and constraints, theoperating frequency for a specific processor may be permanently fusedsuch that processor performance running a worst case workload in a worstcase environment may be substantially lower than could be achieved whenrunning a typical workload in a typical operating environment.Accordingly, achievable processor frequency may be left unused as aresult of the worst case corner operating conditions. Furthermore, thedelta between the fused frequency and achievable frequency is growing asmulti-core processors become more common-place.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description is provided with reference to the accompanyingfigures. In the figures, the left-most digit(s) of a reference numberidentifies the figure in which the reference number first appears. Theuse of the same reference numbers in different figures indicates similaror identical items.

FIGS. 1, 3, and 4 illustrate block diagrams of computing systems inaccordance with various embodiments of the invention.

FIG. 2 illustrates a flow diagram of a method, according to anembodiment.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forth inorder to provide a thorough understanding of various embodiments.However, various embodiments of the invention may be practiced withoutthe specific details. In other instances, well-known methods,procedures, components, and circuits have not been described in detailso as not to obscure the particular embodiments of the invention.Further, various aspects of embodiments of the invention may beperformed using various means, such as integrated semiconductor circuits(“hardware”), computer-readable instructions organized into one or moreprograms (“software”), or some combination of hardware and software. Forthe purposes of this disclosure reference to “logic” shall mean eitherhardware, software, or some combination thereof.

Some of the embodiments discussed herein may provide techniques forimproving IC performance across a range of operating conditions and/orphysical constraints. In one embodiment, operating frequency and/oroperating voltage may be adjusted based on workload and/or operatingconditions, such that performance is improved (e.g., maximized) acrossvarious operating conditions. In some embodiments, the operatingfrequency and/or operating voltage are increased until one or more ofthe operating condition limits are reached. Moreover, frequency may beincreased when there is some indication that the operating system isable to utilize the additional performance made available by theprocessor.

Additionally, some embodiments may be provided in various environments,such as those discussed with reference to FIGS. 1-4. More particularly,FIG. 1 illustrates a block diagram of a computing system 100, accordingto an embodiment of the invention. The system 100 may include one ormore processors 102-1 through 102-N (generally referred to herein as“processors 102” or “processor 102”). The processors 102 may communicatevia an interconnection network or bus 104. Each processor may includevarious components, some of which are only discussed with reference toprocessor 102-1 for clarity. Accordingly, each of the remainingprocessors 102-2 through 102-N may include the same or similarcomponents discussed with reference to the processor 102-1.

In an embodiment, the processor 102-1 may include one or more processorcores 106-1 through 106-M (referred to herein as “cores 106” or moregenerally as “core 106”), a shared cache 108, and/or a router 110. Theprocessor cores 106 may be implemented on a single integrated circuit(IC) chip. Moreover, the chip may include one or more shared and/orprivate caches (such as cache 108 and/or cache 116-1), buses orinterconnections (such as a bus or interconnection network 112), memorycontrollers (such as those discussed with reference to FIGS. 3 and 4),or other components.

In one embodiment, the router 110 may be used to communicate betweenvarious components of the processor 102-1 and/or system 100. Moreover,the processor 102-1 may include more than one router 110. Furthermore,the multitude of routers (110) may be in communication to enable datarouting between various components inside or outside of the processor102-1.

The shared cache 108 may store data (e.g., including instructions) thatare utilized by one or more components of the processor 102-1, such asthe cores 106. For example, the shared cache 108 may locally cache datastored in a memory 114 for faster access by components of the processor102. In an embodiment, the cache 108 may include a mid-level cache (suchas a level 2 (L2), a level 3 (L3), a level 4 (L4), or other levels ofcache), a last level cache (LLC), and/or combinations thereof. Moreover,various components of the processor 102-1 may communicate with theshared cache 108 directly, through a bus (e.g., the bus 112), and/or amemory controller or hub. As shown in FIG. 1, in some embodiments, oneor more of the cores 106 may include a cache (116-1) such as a level 1(L1) cache (generally referred to herein as “cache 116”).

As shown in FIG. 1, the processor 102-1 may also include an active corelogic 120 (e.g., to monitor the operational status of cores 106 and/ordetermine the level of activity (for example, the number of the cores106 or their execution unit(s) that are in an active state, for example,processing data and/or instruction(s)) or the operating frequency orvoltage of the cores) and a storage unit 122 (e.g., to store thresholdvalue(s) for cores 106). As discussed further herein, the storedthreshold values 122 may be utilized by an adjustment logic 124 (e.g.,in conjunction with information from a monitoring logic 126) to increaseand/or decrease operating frequency and/or voltage of one or more of thecores 106 in accordance with some embodiments. Moreover, even thoughlogic 120, logic 124, logic 126, and storage unit 122 are shown to beincluded within the processor 102-1, one or more of the items 120-126may be located elsewhere in the system 100 (e.g., within otherprocessors 102, other components of system 100, etc.).

FIG. 2 illustrates a flow diagram of a method 200 to adjust performanceof a multiple-core processor, according to an embodiment. In oneembodiment, various components discussed with reference to FIGS. 1, 3,and 4 may be utilized to perform one or more of the operations discussedwith reference to FIG. 2. For example, the method 200 may be used toadjust the performance of the processors 102 of FIG. 1 and/or processorsdiscussed with reference to FIG. 3 or 4.

Referring to FIGS. 1-2, at an operation 202, it may be determinedwhether a change in number of active cores has occurred (e.g., activecore logic 120 may determine whether a change in the number of cores 106that are active has occurred). In some embodiments, the operation 202may determine whether there is a change in the level of activity ofcores (e.g., by considering core operating frequency or voltage, thenumber of execution units enabled, etc.). If a change has occurred, atan operation 204, the allowable operating parameter, including forexample operating frequency and/or operating voltage (e.g., asdetermined by reference to the storage unit 122), for one or more cores106 may be adjusted. For example, adjustment logic 124 may cause theoperating frequency and/or voltage of one or more of the cores 106 to beadjusted (e.g., by the logic 124).

If no change has occurred at operation 202 (or after operation 204), theoperating condition of the corresponding processor may be determined atan operation 206. In an embodiment, the current operating condition orbehavior (e.g., current power usage, operating current (Icc),temperature, operating voltage, etc.) is monitored by a logic 126, e.g.,provided in a corresponding processor (such as processor 102-1 shown inFIG. 1 or within a system such as system 100 of FIG. 1). In someembodiments, the logic 120 may be provided within logic 126. Moreover,the monitoring logic 126 may be coupled to one or more sensors (notshown) that correspond to the processor component(s) or core(s) beingmonitored to determine the operating conditions discussed herein (e.g.,current power usage, operating current (Icc), temperature, operatingvoltage, etc.).

At operations 208 and 212, the condition(s) determined at operation 206may be compared against operating condition constraint(s)/threshold(s)(e.g., the adjustment logic 124 may compare the condition(s) determinedby the monitoring logic 126 with values stored in the storage unit 122at operation 208). Based on the comparisons, the operating parametersmay be adjusted dynamically, for example, an operating parameter may beadjusted upward (at operation 214) when the current behavior is belowall or most (or at least some) of the limit(s)/threshold(s) and downward(at operation 210) when the current behavior is at or above one or moreof the limit(s)/threshold(s).

Further, in some embodiments, thermal design power (TDP), maximumoperating current (Icc_max), and/or thermal design current (Icc_TDC) maybe monitored (e.g., by logic 126), in addition to temperature, maximumoperating voltage (Vmax), and/or maximum frequency. Because someconstraints may not be dynamically monitored fast enough to changebehavior in time to avoid or reduce violating specifications, Icc_max,Vmax, and/or maximum frequency may be limited by “fusing” differentoperating limits (e.g., or implemented as stored values in unit 122)based on the number of active processor cores (as determined by thelogic 120), for example. In an embodiment, the maximum frequency may bedifferent when a single processor core is active than when multipleprocessor cores are active. By monitoring such constraints, anembodiment may improve performance across various workloads.

Moreover, in order to ensure that other physical constraints on aprocessor are not exceeded, two or more operating parameter values maybe fused (or stored as a value in storage unit 122) in one embodiment:one or more for the condition when multiple processor cores are active,and the other for the condition when only one of the processor cores isactive. This approach may allow a multi-core processor to increasefrequency when only one core is active, but it is not able to takeadvantage of other variations in workload. For example, in anembodiment, all single core workloads may be run at one fused or storedfrequency, independent of the power consumed or operating temperature,and all multi-core workloads may be run at another frequency,independent of power consumption or other physical constraints.Accordingly, the frequency achievable may be dynamically adjusted by themonitored constraints. Further, performance may be increased onlow-power workloads, without requiring an increase in systemcapabilities (e.g., thermal or power delivery). As processors add morecores, such embodiments allow for scaling of single-thread performance,while achieving the benefits of multiple cores on workloads that areable to utilize them. Additionally, the techniques discussed herein maybe applied to any type of a multiple-core processor, such as graphicsprocessors, network processors, etc.

FIG. 3 illustrates a block diagram of a computing system 300 inaccordance with an embodiment of the invention. The computing system 300may include one or more central processing unit(s) (CPUs) 302 orprocessors that communicate via an interconnection network (or bus) 304.The processors 302 may include a general purpose processor, a networkprocessor (that processes data communicated over a computer network303), or other types of a processor (including a reduced instruction setcomputer (RISC) processor or a complex instruction set computer (CISC)).Moreover, the processors 302 may have a single or multiple core design.The processors 302 with a multiple core design may integrate differenttypes of processor cores on the same IC die. Also, the processors 302with a multiple core design may be implemented as symmetrical orasymmetrical multiprocessors. In an embodiment, the operations discussedwith reference to FIGS. 1-2 may be performed by one or more componentsof the system 300.

A chipset 306 may also communicate with the interconnection network 304.The chipset 306 may include a memory control hub (MCH) 308. The MCH 308may include a memory controller 310 that communicates with a memory 312.The memory 312 may store data, including sequences of instructions, thatare executed by the CPU 302, or any other device included in thecomputing system 300. In one embodiment of the invention, the memory 312may include one or more volatile storage (or memory) devices such asrandom access memory (RAM), dynamic RAM (DRAM), synchronous DRAM(SDRAM), static RAM (SRAM), or other types of storage devices.Nonvolatile memory may also be utilized such as a hard disk. Additionaldevices may communicate via the interconnection network 304, such asmultiple CPUs and/or multiple system memories.

The MCH 308 may also include a graphics interface 314 that communicateswith a display device 316. In one embodiment of the invention, thegraphics interface 314 may communicate with the display device 316 viaan accelerated graphics port (AGP). In an embodiment of the invention,the display 316 (such as a flat panel display) may communicate with thegraphics interface 314 through, for example, a signal converter thattranslates a digital representation of an image stored in a storagedevice such as video memory or system memory into display signals thatare interpreted and displayed by the display 316. The display signalsproduced by the display device may pass through various control devicesbefore being interpreted by and subsequently displayed on the display316.

A hub interface 318 may allow the MCH 308 and an input/output controlhub (ICH) 320 to communicate. The ICH 320 may provide an interface toI/O device(s) that communicate with the computing system 300. The ICH320 may communicate with a bus 322 through a peripheral bridge (orcontroller) 324, such as a peripheral component interconnect (PCI)bridge, a universal serial bus (USB) controller, or other types ofperipheral bridges or controllers. The bridge 324 may provide a datapath between the CPU 302 and peripheral devices. Other types oftopologies may be utilized. Also, multiple buses may communicate withthe ICH 320, e.g., through multiple bridges or controllers. Moreover,other peripherals in communication with the ICH 320 may include, invarious embodiments of the invention, integrated drive electronics (IDE)or small computer system interface (SCSI) hard drive(s), USB port(s), akeyboard, a mouse, parallel port(s), serial port(s), floppy diskdrive(s), digital output support (e.g., digital video interface (DVI)),or other devices.

The bus 322 may communicate with an audio device 326 (e.g., tocommunicate and/or process audio signals), one or more disk drive(s)328, and a network interface device 330 (which is in communication withthe computer network 303). Other devices may communicate via the bus322. Also, various components (such as the network interface device 330)may communicate with the MCH 308 via a high speed (e.g., generalpurpose) I/O bus channel in some embodiments of the invention. Inaddition, the processor 302 and the MCH 308 may be combined to form asingle chip. Furthermore, a graphics accelerator may be included withinthe MCH 308 in other embodiments of the invention.

Furthermore, the computing system 300 may include volatile and/ornonvolatile memory (or storage). For example, nonvolatile memory mayinclude one or more of the following: read-only memory (ROM),programmable ROM (PROM), erasable PROM (EPROM), electrically EPROM(EEPROM), a disk drive (e.g., 328), a floppy disk, a compact disk ROM(CD-ROM), a digital versatile disk (DVD), flash memory, amagneto-optical disk, or other types of nonvolatile machine-readablemedia that are capable of storing electronic data (e.g., includinginstructions).

FIG. 4 illustrates a computing system 400 that is arranged in apoint-to-point (PtP) configuration, according to an embodiment of theinvention. In particular, FIG. 4 shows a system where processors,memory, and input/output devices are interconnected by a number ofpoint-to-point interfaces. The operations discussed with reference toFIGS. 1-3 may be performed by one or more components of the system 400.

As illustrated in FIG. 4, the system 400 may include several processors,of which only two, processors 402 and 404 are shown for clarity. Theprocessors 402 and 404 may each include a local memory controller (MC)406 and 408 to enable communication with memories 410 and 412. Thememories 410 and/or 412 may store various data such as those discussedwith reference to the memory 312 of FIG. 3.

In an embodiment, the processors 402 and 404 may be one of theprocessors 302 discussed with reference to FIG. 3. The processors 402and 404 may exchange data via a point-to-point (PtP) interface 414 usingPtP interface circuits 416 and 418, respectively. Further, theprocessors 402 and 404 may include a high speed (e.g., general purpose)I/O bus channel in some embodiments of the invention to facilitatecommunication with various components (such as I/O device(s)). Also, theprocessors 402 and 404 may each exchange data with a chipset 420 viaindividual PtP interfaces 422 and 424 using point-to-point interfacecircuits 426, 428, 430, and 432. The chipset 420 may further exchangedata with a graphics circuit 434 via a graphics interface 436, e.g.,using a PtP interface circuit 437.

At least one embodiment of the invention may be provided within theprocessors 402 and/or 404. For example, one or more of the componentsdiscussed with reference to FIGS. 1-2 may be provided in the processors402 and/or 404. Other embodiments of the invention, however, may existin other circuits, logic units, or devices within the system 400 of FIG.4. Furthermore, other embodiments of the invention may be distributedthroughout several circuits, logic units, or devices illustrated in FIG.4.

The chipset 420 may communicate with a bus 440 using a PtP interfacecircuit 441. The bus 440 may communicate with one or more devices, suchas a bus bridge 442 and I/O devices 443. Via a bus 444, the bus bridge442 may communicate with other devices such as a keyboard/mouse 445,communication devices 446 (such as modems, network interface devices, orother communication devices that may communicate with the computernetwork 303), audio I/O device 447, and/or a data storage device 448.The data storage device 448 may store code 449 that may be executed bythe processors 402 and/or 404.

In various embodiments of the invention, the operations discussedherein, e.g., with reference to FIGS. 1-4, may be implemented ashardware (e.g., logic circuitry), software, firmware, or combinationsthereof, which may be provided as a computer program product, e.g.,including a machine-readable or computer-readable medium having storedthereon instructions (or software procedures) used to program a computerto perform a process discussed herein. The machine-readable medium mayinclude a storage device such as those discussed with respect to FIGS.1-4.

Additionally, such computer-readable media may be downloaded as acomputer program product, wherein the program may be transferred from aremote computer (e.g., a server) to a requesting computer (e.g., aclient) by way of data signals embodied in a propagation medium via acommunication link (e.g., a bus, a modem, or a network connection).

Reference in the specification to “one embodiment,” “an embodiment,” or“some embodiments” means that a particular feature, structure, orcharacteristic described in connection with the embodiment(s) may beincluded in at least an implementation. The appearances of the phrase“in one embodiment” in various places in the specification may or maynot be all referring to the same embodiment.

Also, in the description and claims, the terms “coupled” and“connected,” along with their derivatives, may be used. In someembodiments of the invention, “connected” may be used to indicate thattwo or more elements are in direct physical or electrical contact witheach other. “Coupled” may mean that two or more elements are in directphysical or electrical contact. However, “coupled” may also mean thattwo or more elements may not be in direct contact with each other, butmay still cooperate or interact with each other.

Thus, although embodiments of the invention have been described inlanguage specific to structural features and/or methodological acts, itis to be understood that claimed subject matter may not be limited tothe specific features or acts described. Rather, the specific featuresand acts are disclosed as sample forms of implementing the claimedsubject matter.

What is claimed is:
 1. A processor comprising: a plurality of processorcores; active core logic to determine a change in a number of theplurality of processor cores that are in an active state; monitoringlogic to determine operating conditions of the active processor cores,wherein the operating conditions include current power usage, maximumoperating current, thermal design power, thermal design current, andmaximum operating voltage, and compare the determined operatingconditions of the processor cores to a threshold value; and adjustmentlogic to adjust an operating parameter of the processor cores inresponse to the comparison of the operating condition to the thresholdvalue, wherein the adjustment logic is to increase a value of theoperating parameter in response to the operating condition indicating avalue that is lower than the threshold value and to decrease a value ofthe operating parameter in response to the operating conditionindicating a value that is higher than or equal to the threshold value,wherein an operating condition for when multiple processor cores of theplurality of cores are to be active and an operating condition for onlya single processor core of the plurality of cores is to be active arefused to comprise the threshold value and wherein all single coreworkloads are fused at a single frequency that is independent of powerconsumed or operating temperature.
 2. The processor of claim 1, whereinthe operating parameter comprises one or more of: (a) an operatingfrequency of one or more of the plurality of processor cores; or (b) anoperating voltage of one or more of the plurality of processor cores. 3.The processor of claim 1, further comprising one or more sensors todetect the operating condition.
 4. The processor of claim 1, wherein theoperating condition correspond to one or more of the plurality ofprocessor cores.
 5. The processor of claim 1, wherein one or more of theplurality of processor cores and one or more of the first logic, or thesecond logic are on a same integrated circuit die.
 6. A methodcomprising: determining that there is no change in a number of activeprocessor cores; determining current operating conditions of the activeprocessor cores, wherein the operating conditions include current powerusage, maximum operating current, thermal design power, thermal designcurrent, and maximum operating voltage; comparing the determined currentoperating condition of the active processor cores to a stored thresholdvalue; adjusting the operating parameter by increasing a value of theoperating parameter in response to the one or more operating conditionsindicating a value that is lower than the threshold value and decreasinga value of the operating parameter in response to the one or moreoperating conditions indicating a value that is higher than or equal tothe threshold value; wherein an operating condition for when multipleprocessor cores of the plurality of cores are to be active and anoperating condition for only a single processor core of the plurality ofcores is to be active are fused to comprise the threshold value andwherein all single core workloads are fused at a single frequency thatis independent of power consumed or operating temperature.
 7. The methodof claim 6, further comprising storing the threshold value in a storageunit of the processor.
 8. A computing system comprising: a memory tostore one or more threshold values; and a processor having a pluralityof processor cores, the processor comprising: active core logic todetermine a change in a number of the plurality of processor cores thatare in an active state; monitoring logic to determine one or moreoperating conditions within the active processor cores, wherein theoperating condition is selected from one or more of: current powerusage, operating current, and operating voltage, and compare the one ormore determined operating conditions to a stored threshold value; andadjustment logic to dynamically adjust an operating parameter of one ormore of the plurality of processor cores in response to comparing theone or more operating conditions to the stored threshold value, whereinthe adjustment logic is to increase a value of the operating parameterin response to the operating condition indicating a value that is lowerthan the threshold value and to decrease a value of the operatingparameter in response to the operating condition indicating a value thatis higher than or equal to the threshold value, wherein an operatingcondition for when multiple processor cores of the plurality of coresare to be active and an operating condition for only a single processorcore of the plurality of cores is to be active are fused to comprise thethreshold value and wherein all single core workloads are fused at asingle frequency that is independent of power consumed or operatingtemperature.
 9. The system of claim 8, wherein the operating parametercomprises one or more of: (a) an operating frequency of one or more ofthe plurality of processor cores; or (b) an operating voltage of one ormore of the plurality of processor cores.
 10. The system of claim 8,further comprising one or more sensors to detect the one or moreoperating conditions.
 11. The system of claim 8, further comprising anaudio device coupled to the processor to communicate audio signals. 12.The processor of claim 1, wherein a processor core is in the activestate while it is processing data or an instruction.
 13. The processorof claim 1, wherein the monitoring logic to compare the operatingcondition of the processor cores to a second threshold.